This study will evaluate ways to improve magnetic resonance angiography (MRA) for diagnosing atherosclerosis. Patients with atherosclerosis who have had conventional angiography at Suburban Hospital in Bethesda, Maryland, will be considered for this study. Those enrolled will have a MRA scan at Suburban Hospital within 72 hours of their conventional angiogram. This protocol enables state-of-the-art technology developed in the Diagnostic Radiology Department, Clinical Center to be applied to patients with atherosclerotic disease with angiographic correlation. We are currently investigating improved methods of k-space ordering to allow rapid scanning of the run-off vessels while obtaining high resolution images of the vessels. Additional investigations will include real time MR "fluoroscopy" to provide better timing of the MR during intravenous gadolinium chelate administration. Improvements in the MRA "package" may allow substitution of MRA for conventional catheter angiography in the near future.